Dick’s Sporting Goods (DKS), one of America’s largest sports retailers, yesterday has announced that it will no longer sell military-style semi-automatic rifles and that customers buy firearms from its stores will have to be older than 21.

Additionally, the company is immediately ending its sales of high-capacity magazines, and backing “common sense gun reform”. The announcement by Dick’s Sporting Goods came as teachers and students of Marjory Stoneman Douglas High School made an emotional return to class.

The company’s CEO, Ed Stack made the announcement on Wednesday on ABC’s Good Morning America. Stack said the teenage gunman allegedly behind the massacre that claimed 17 lives and injured many more in Parkland, FL had purchased a weapon from the retailer last year.

Although the 19-year-old gunman did not use that firearm — a shotgun —  in the shooting, Stack said the revelation profoundly affected him and his coworkers at the company.

“We did everything by the book. We did everything that the law required, and still, he was able to buy a gun. When we looked at that, we said the systems that are in place across the board just aren’t effective enough to keep us from selling a gun like that. And so we have decided we are not going to sell the assault-type rifles any longer,” Stack said.

The announcement generated thousands of responses against and for on the company’s social media pages. Dick’s cut off sales of military-style firearms after the Sandy Hook Elementary School shooting six years ago.

However, sales had begun again at its Field & Stream stores, which consist of 35 outlets spread sixteen states as of October 2016. On Wednesday, the CEO said that would also end, and called on legislators to take action. Stack urged lawmakers to ban military-style weapons, high-capacity magazines and bump stocks, and raise the minimum age to purchase guns to 21.